Glazing beads have long been known for holding panels and glass panes in appropriate frame members. Among the patent literature there may be mentioned the U.S. Pat. Nos. to James 3,487,601; Wendt 4,463,535; Letarte 3,674,082; Rollyson 4,132,044; Blanchett 4,335,552; preu 3,982,371; Litchfield 4,525,966; Johnson 4,742,664; Peters 1,223,609; Owen 3,196,998; van Eerden 4,555,884; Owen 3,016,993; and Di Fazio 3,872,638. Among these, there are known glazing beads which snap lock into place in one way or another, such as those shown in the U.S. Pat. Nos. to Johnson '664, the Blanchett et al patent '552 and the Rollyson patent '044. Some of these have portions which are springy, flexible or elastic such as James patent '601 and Preu patent '371.
Those glazing beads shown in the aforementioned U.S. patents are typical and many others have appeared in the marketplace over the years. These prior constructions have come and gone, and most have served in a suitable but not fully satisfactory fashion. Insofar as is known, however, no prior glazing bead construction has met the requirements of being easily installed to lock the panel or pane in place, constructed in such a way so that the panel or pane is well retained with the glazing bead being positively locked in the extruded sash with little or no chance of accidental uncoupling, while still being capable of easy unlocking and withdrawal for removal of a broken pane or panel. The prior glazing bead constructions can either not be removed once they are installed, can be removed only with great difficulty with substantial force required to overcome large frictional forces as portions of the glazing bead are dragged across the surface of the pane or panel, or they fail to lock in a sufficiently positive manner and can thus be accidentally displaced, or they suffer from two or more of these defects.